Persistence of salmonella enteritidis in poultry units and poultry food

1. Studies on the survival of Salmonella enteritidis in poultry units and food were carried out over a two‐year period.

2. The organism persisted for at least one year in an empty trial house at the laboratory in which naturally‐infected broiler breeder birds had previously been housed. A similar survival period was seen in a building which had housed an infected layer breeder flock, although infection was not detected in a subsequent pullet flock.

3. Salmonella enteritidis was also frequently found surviving outside poultry houses in small pockets of litter and fan dust which had been left after cleansing and disinfection of the site. On some poultry units S. enteritidis was also found in wild bird droppings.

4. Salmonella contamination appeared to persist preferentially in association with dust particles swept from the floor and in food troughs and S. enteritidis survived at least 26 months in artificially contaminated poultry food.     

Purification and characterisation of chicken liver monomeric glutathione peroxidase

1. A novel glutathione peroxidase, which is distinct from tetrameric glutathione peroxidase, was purified to homogeneity from a broiler chick liver cytosolic fraction using 5 different column chromatographic methods.

2. The enzyme in cytosol was separated from ‘classic’ tetrameric glutathione peroxidase and glutathione S‐transferases by DEAE‐Sephacel and Sephadex G‐100 chromatographies and further purified by Mono Q, hydroxylapatite and sulphobro‐mophthalein‐S‐glutathione‐agarose chromatographies.

3. The molecular weight of the purified enzyme determined by sodium dodecyl sulphate‐polyacrylamide gel electrophoresis was 19,500 and that found by gel filtration chromatography was comparable. This indicates that the enzyme protein is a single polypeptide. The isoelectric point of the enzyme was determined as 7.0 by polyacrylamide gel isoelectric focusing.

4. The purified enzyme catalysed the reduction of hydrogen peroxide, cumene hydroperoxide, tert‐butyl hydroperoxide and linoleic acid hydroperoxide. Furthermore, it reduced phosphatidylcholine hydroperoxide in the absence of phospholi‐pase A2. The optimum pH for the enzyme reaction was 7.0. The antiserum against the purified enzyme reacted with the 19.5 kDa polypeptide in the liver cytosol of duck and quail.     

Performance of broiler chicks fed on alkali‐treated neem (Azadirachta indica) kernel cake as a protein supplement

1. An experiment was conducted to evaluate growth and nutrient efficiency of broiler chicks from 3 to 42 d fed on diets containing alkali‐treated neem (Azadirachta indica A. juss) kernel cake (NKC) as a protein supplement in place of peanut meal (PNM).

2. NKC was treated with sodium hydroxide at 10 (ANKC 1) or 20 g (ANKC 2)/kg and incorporated into the test diets at 135 or 300 g/kg to replace 50 (low—L) or 100 (High—H) % of the PNM protein of the reference diet.

3. Despite comparable retentions of dry matter and total carbohydrate on L‐ANKC 1 and 2, fibre on L‐and H‐ANKC 2 and nitrogen, calcium and acid detergent fibre on all experimental diets compared to the retentions of chicks on the reference diet, only the chicks fed L‐ANKG 2 were found to grow and utilise food as well as those on the reference diet.

4. The activities of serum alkaline phosphatase on H‐ANKC 1 and alanine amino transferase on all test diets were depressed (P < 0.05), but the activity of serum aspartate amino transferase, total erythrocyte count and concentration of blood haemoglobin and urea were similar in all chicks.

5. No significant differences were noticed in the qualitative and quantitative characteristics of the meat of chicks fed on the reference diet and on diets incorporating ANKC at the lower concentrations. Feeding ANKC protein did not impart any untoward taste as evaluated in pressure cooked meat by a semitrained panel on a 7 point Hedonic scale.

6. Except for duodenal and jejunal inflammation in chicks on both reference and test diets, all the vital organs were normal, ruling out any adverse affects caused by residual neem bitters.

7. Comparable performance and cost of chicks fed on the reference and L‐ANKC 2 diets, warrants the utilisation of hitherto wasted protein‐rich NKC after alkali treatment in broiler chick diets to spare peanut meal for human consumption in developing countries.     

Changes in blood and spleen lymphocyte populations following antigen challenge in immature male chickens

1. The effects of antigen (Ag) injection on the distribution of lymphocyte populations of Cornell K‐strain male chickens were studied.

2. Two experiments were conducted. In the first, chickens were injected with Brucella abortus (BA), a purported T‐independent antigen. In the second, chickens were injected with sheep red blood cells (SRBC), a T‐dependent antigen. Peripheral blood lymphocytes (PBL) and spleen lymphocytes isolated at 0, 3, 6, 9, 12 and 24 h following Ag injection were stained with monoclonal antibodies (mAb) detecting B‐lymphocytes, CD4⁺ and CD8⁺ cells.

3. B‐lymphocytes in the blood or spleen showed no significant changes following either BA or SRBC injection. In contrast, CD4⁺ cells were decreased in the blood and increased in the spleen following BA and SRBC injections. CD8⁺ cells were decreased in both blood and spleen following BA injection but were unchanged in either blood or the spleen following SR8C injection.

4. These results indicate that there is a change in both spleen and circulating lymphocyte populations, especially T‐helper cells, following Ag injection. T‐helper cells are apparently the primary population involved in the initiation of humoral immunity.     

Soluble matrix of hen's eggshell extracts changes in vitro the rate of calcium carbonate precipitation and crystal morphology

1. Extra and intramineral eggshell matrix proteins were solubilised before and after demineralisation by sequential extractions using guanidine hydrochloride and EDTA.

2. The intramineral electrophoretic profile of SDS‐PAGE showed the presence of 80, 66, 43, 36 and 15 kDa bands with a predominance of a 17 kDa band. In the extramineral part, the major protein was the 15 kDa band.

3. The introduction of intramineral extract to a metastable solution of calcium carbonate delayed the rate of crystal growth. The delay in the rate of precipitation was elicited by a single fraction (MW 50–80 kDa), isolated by gel filtration chromatography, of eggshell extracts. Extramineral extracts had no effect.

4. Addition in vitro of intramineral eggshell extracts modified the morphology of calcite; the crystals aggregated and showed irregular surfaces.

5. These observations suggest that constituents of the eggshell matrix are involved in the control of calcite growth and crytallographic structure of the hen's eggshell.     

Artificial increase of eggshell conductance improves hatchability of early laid goose eggs

1. The purpose of this work was to test the possibility of increasing the hatchability of goose eggs with low mass specific eggshell gas conductance (G_sp), by drilling holes through the eggshell into the air cell, and thus solving both the low water loss rate and low oxygen availability problems.

2. A linear relationship was found between the area of a hole drilled and the apparent increase in eggshell gas conductance (G). Drilling more than one hole increased apparent G 3.6 times more than one hole only, of the same total area.

3. Hole‐drilling did not increase egg contamination. The drilling of a 5 mm² hole on day 17 of incubation increased hatchability both in laboratory tests and in commercial hatcheries (6.1% and 10.5% respectively).

4. Drilling holes on days 15 to 22 of incubation increased hatchability when the predicted mean water loss was lower than 14%. Drilling on day 25 did not have a significant effect, and drilling on day 11 of incubation was too early.

5. Drilling a hole into the aircell (during the second half of incubation) may increase hatchability of low conductance eggs, although oxygen pressure under the eggshell should then be checked in order to evaluate oxygen availability to the embryo.     

Effect of dietary protein content on live and carcase performance of heterozygous naked neck and normally feathered broilers

1. An experiment was conducted to determine the effect of different dietary protein contents on the performance of naked neck (Na/na) and normally feathered (na/na) broilers.

2. Chicks from the two genotypes were reared in wire‐floored cages and divided at random into 3 groups. Birds were fed on high protein (HP, 12.99 MJ ME, 238 g crude protein/kg and 12.94 MJ ME, 216 g crude protein/kg from 0 to 3 and 3 to 7 weeks, respectively), medium protein (MP, 12.99 MJ ME, 219 g crude protein/kg and 12.87 MJ ME, 201 g crude protein/kg from 0 to 3 and 3 to 7 weeks), and low protein (LP, 12.94 MJ ME, 205 g crude protein/kg and 12.75 MJ ME, 184 g protein/kg from 0 to 3 and 3 to 7 weeks) diets.

3. The LP diets resulted in a significantly lower daily body weight gain of males from 0 to 3 weeks. Dietary protein content had no effect on body weight gain from 3 to 7 weeks, body weight at 7 weeks, and the food intake of birds. Carcase composition of birds from both genotypes was unaffected by dietary protein.

4. Naked neck birds had significandy higher body weights at 7 weeks. Yields of carcase and breast of Na/na males were significantly higher than those of na/na males. There were no significant differences between females from the two genotypes as regards carcase yield.

5. It was concluded that the dietary protein requirements of naked neck birds were similar to those for normally feathered birds.     

Evaluation of postoperative complications following elective surgeries of dogs and cats at private practices using computer records.

This study was designed to determine the frequency of postoperative complications following elective surgeries (castration, ovariohysterectomy, onychectomy) of dogs and cats from private practices and to evaluate the use of electronic medical records for this type of research. All elective surgeries performed during the study period at 5 private practices were included. The surgical techniques and materials used for each procedure were similar across practices, but the interpretation of "complication," the amount of detail recorded on the primary medical record, and the intensity of follow-up varied. The frequencies and types of complications varied by species and procedure. The postoperative complication frequencies ranged from 1% to 24% for all complications and 1% to 4% for severe complications. The results of this study describe populations of elective-surgery patients at private practices, provide data for educating clients about the risks associated with these procedures, and demonstrate how computerized records can be used to collect practice-specific medical information.     

Prevalence and duration of insensibility following electrical stunning in calves

Sixty-one calves were electrically stunned with 100-250 V currents (103-1806 mA) and the prevalence and duration of insensibility was assessed from their physical behaviour, the presence of epileptiform activity in their electrocorticograms, and the absence of visual evoked responses in their electrocorticograms. A current applied at 100 V across the head for 3 s failed to induce insensibility in all cases. Currents at 150-250 V induced insensibility in all calves and the shortest duration of insensibility was 44 s. It is recommended that a 150-200 V current would be appropriate for commercial use.     

Mortality in near‐term ostrich embryos during artificial incubation

1. The ostrich industry in South Africa (and elsewhere) experiences a high rate of embryo mortality during artificial incubation of eggs. Most of this mortality takes place in the last 10–14 d of incubation.

2. We carried out post‐mortem examinations on 111 embryos that died within this period to assess the causes of this mortality.

3. Malpositioning and severe oedema were the predominant symptoms of dead‐in‐shell embryos with 55% being malpositioned and 41% showing severe oedema. Of these, 22 embryos (24%) showed both symptoms. Malpositioning generally results from incorrect setting of the eggs or inadequate turning and oedema was significantly correlated with the amount of water lost from the eggs which in turn was correlated with egg size.

4. Myopathy, gross lesions of internal organs, haemorrhage, bacterial infections and congenital deformities were found in less than 10% of chicks examined for these symptoms.